Two-cycle internal-combustion engine



March 13, 1928.

A. O. ANDERSEN TWO-CYCLE INTERNAL'COMBUSTION ENGINE Filed Dec. 5; 1923 2 Sheets-Sheet 1 March 13, 1928.

A. 0. ANDERSEN TWO-CYCLE INTERNAL COMBUSTION ENGINE Filed Dec. 5, 1923 2 Sheets-Sheet 2 iii . pickup.

It 18 also an ob ect of the 1l1V111Z1011.t-0' provide an improved means o'fcooling the Patented Mar. 13, 1928.

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ALFRED? 0. Annnnsnn, or :nmnenronr, CONNECTICUT,

TWO-CYCLE rnrnnnan-oonnnsrron ENGINE.

Application filed December .5, 1823. Serial No. 678,609.

This invention relates to internalcombus" tion engines, particularly of the twocycle type, andhas for an object to. providean' internal combustion engine which will run better with a simple type of carburetorthan will the usual 'lour cycle engine, that will have a greater 'eificiency and operate at a greater economy over a large range of power, which will give a greater horse power for a given weight of engine, which can be throttled down much further. than the 'or-.

dinary tour-cycle engine, thus reducing the frequency of the necessity for shifting gears when the engine is employed for automobile use and which willhave. a more rapid piston and the cylinder.

lVith the -loregoin'g' and other objects in view, I have devised the construction illustrated in the accompanying drawings, iorming a part ofthis specification,"similar'reference numerals being employed throughout the various figures to indicate correspond ing elements. 'In these drawings,

-Fig. 1 1s a cross section througha cylinder of an engine embodying my invention, show-' ing the piston at the end of the power stroke.

Fig. 2 is a similar view showing the pistonat tlie endof the compression stroke- Fig. 3 is a transverse section through a,

portion of the cylinder substantially on line 3-3 of Fig. 2. 1

Fig. %l is a side elevation of one 'of'the gas crmducting means, the View being substantially on limee of Fig. 1.

Fig. 5 is a partial section and'elevation oi theconne'ction between the piston rod" and the crank, the sectionbeing substantially on line5- 5 of Fig. 1, and:

13 I have for convenience termed thepump chamber. The upper end of the-cylinder is closed by the head 14 and the lower end by the'lower wall thereof, as shown'at 30.

the head 15. In the upper headis thefuel inlet passage 16leading from any suitable type ofcarburetor (not shown) and con-, trolled bythe'inlet valve 17 normally held closed by the usualspring 18. Als'o car-ried by thishead is the spark plug 19 connected by lead 20 to the usual ignition controlling device. a

I prefer to makethe piston hollow in the present construction and provide 1 the lower wall of thepiston'with one orinore exhaust passages 21lead1ng to the chamber 22' in the piston, these exhaustpassages being con-- trolled by'the exhaust valves 23. These valves may be mounted in. dilierentwaysbut;' I, prefer that substantially as shown wherein guide rods 24 are threaded into the upper wall of: the piston, as shown at 25,

and extend through the valves 23, the valves being adapted to slide on these rods and-are normally held in closed position by the sprlngs 2-6 embracing the rods and engaging the collars 27; The piston rod28in thewpres ent instance is a tubelcading from the Cl1lI11-' her; 22 in the, piston, and'the entrance to this: 1

tubeis preferably. located:adjacentthe upper Wall ofthe'pistom'that'is,1the wall of the piston next to the combustion chamber, and it leads throughthe lower head 15 wherein it is surrounded by asuitable stutfing box:

29 to prevent leakage ofgas about this rod.-

The rod is connectedto the piston by a'ny suitable means, such asby threading it. into i Surrounding the walls of the cylinder are 1 chambers or passages 31 and 32 for thegases Q orproducts of combustion, whiclrchambers areseparated by a cross wall Leading:

fromthe combustion chamber 12to the up er as chamber 31 are a )luralt of o ene ings orports 34L spaced about its periphery adjacent the lower end of this chamber and passingthrough the walls of the cvlinder.-

These openings are so located that they are uncovered by the pis'tononly when thepis or it's'aextreme outer. position, as shown in ton is adjacent the end of the working stroke" Fig. 1, but-fat other timesareclosed by this piston.- Leading from theloweror pump chamber 13 to the lower gas chamber 32 are aserles of similar openings or ports 35, and

these ports are so located as to he uncovered .by the piston only when itis adjacent its extreme upper position or, that is, at theen'd of the compression stroke. It will 'be noted that the openings 3% and 35 are located on v the openings 34 and 35.

opposite sides of the cross wall '33 and are alternately uncovered and closed by the piston as the piston reciprocates. In order to prevent leakage of gas by the pistonthe cylindrical walls thereof are provided with suitable grooves for carrying the usual packing rings 36. These rings are Preferably placed adjacent the opposite ends of the piston substantially as shown.

For the purpose of conducting .the gases from the uppergas chamber 31 to the lower gas chamber 32 I provide a series of conducting pipes 37 spaced about the walls of the cylinder. I prefer to place them outside the gas chambers, as shown, and they may be secured to the walls of the chamber by any suitable means, such as screws 38. They are also preferably connected with the gas chambers 31 and 32 adjacent the upper and lower ends thereof respectively or, that is, at the opposite ends of these chambers from Extending longitudinally through these gas chambers are anumber of pipes 39. which are preferably cast in position when the cylinder is cast,

and there are preferably a large number of these tubes provided as indicated to give a large cooling surface. These. tubes are adapted-to conduct through the gas chamber a cooling fluid, such as-water, and provide a condenser orcooling means for the exhaust gases after they leave the combustion chamber. To facilitate flow of cooling fluid, such as water, through. these pipes the opposite ends thereof communicate with an annular chamber'40 in the lower head 15 and a similar chamber 41 in the upper head 14, and the cooling water may be conducted to the lower chamber 40 by a suitable supply pipe 42 and conducted from the upper chamber by. pipe 43. It is generally desirable to employ a closed circulating system for this cooling water so that it may be used continuously as in the usual automobile practice, in which case the outlet pipe 43 may be led to the upper end of the usual radiator 44 and the cool water from. the radiator conducted back to the chamber 40 by the pipe 42 in which may be located a circulating pump 45.

The piston rod 28 is connected by a suitable pivotal connection 46 to a connecting rod 47 which in'turn has the usual connection with a crank pin 48 on the crank shaft, but as the exhaustgases are conducted from the piston through the piston rod a branch conductor 49 leads laterally from this rod to a conductor 50 adapted to slide in suitable guides 51 and 52. These guides may be suitably located as desired, but in the drawing one is shown on the exterior of the cylinder and the other in the bottom wall 53 of the crank case. The gases are discharged throu 11 this conductor beneath the crank case, t e upper portion above the branch 49 being closed. This upper portion may be extended,as shown in Fig. 6, to carry a fin ger 54 for operating the inlet valve 17, if it is desired to give this valve positive actuation. I have found that positive actuation of this valve is, however, not necessary as there is suflicient suction in the combustion chamber to open it to draw in the combustible mixture. The finger 54 when used may be adjustably secured to the extension of conductor 50 by means of a suitable set screw 55.

The operation is as follows:

Beginning with the (piston in its lowermost positon or at the on of power stroke, as shown in Fig. 1, and assuming that a charge of combustible mixture from the carburetor, not shown, has been drawn through the inlet 16 into the combustion chamber 12, aspiston 11 moves upwardly it will close the ports 34, the valve 17 will close, and the combustible mixture will be compressed in the chamber 12. When the piston approaches its extreme upper position, as shown in Fig. 2, the charge will be ignited by the spark plug 19 and the piston forced again to its lowermost position. As the piston moves upwardly, however, it creates a vacuum in pump chamber 13, and asthe piston uncovers the openings 35 at the upper end of its stroke this VtlClllllll in the chamber 13 will be transmitted to the exhaust gas chamber 32 tending to reduce the pressure in this chamber and the upper chamber 31, and will draw burned gases from these chambers into the chamber. 13. Now, when the piston is forced downwardly under the action of the explosion the openings 35 will be closed and the exhaust gases in the chamber 13 will be compressed until the pressure is suilicient to open the discharge or outlet valves 23 and forcethese exhaust gases into the chamber 22 in the piston and through the conductor pipe28, branches 49 and 50 to the atmosphere. Immediately the piston approaches the lower end of the stroke the openings 34 are uncovered allowing the exhaust gases to pass into chamber 31. However, the gases in the chambers 31 and 32 are in Contact with the cooling or condenser pipes 39, and so the gases are cooled reducing the pressure in these gas chambers and producing a partial vacuum therein which is augmented by the vacuum produced in the chamber 13 on the up stroke of the piston. Thus when the openings 34 are uncovered, as there is a partial vacuum in the chamber 31, the exhaust gases are immediately drawn through the openings 34 into this chamber and the new charge of combustible mixture is drawn in through the inlet valve 17. By placing the cross wall 33 between the openings 34 and 35 and by connecting the conductor pipes 37 to the chambers 31 and 32 at the upper and lower ends thereof respectively, the hot gases are given extended contact with the cooling ion fill

pipes 39 so that they are thoroughly cooled before they reach the openings 35. By providingalarge number of cooling pipes 39,

equally spacing the conductor pipes 37,

which these gases are exposed. It will also be noted that the conductors 37 communicate with the chambers 31 and 32 on the opposite sides of the chambers from the communication therewith of the openings 84 and 35 so that the gases in passing from the openings 34 to the pipes 37 or from the pipes 37 to the openings 35 must pass laterally across the cooling pipes. It is still further to be noted that the cooling water at its lower temperature is in the portion of the pipes 39 which are in the lower or cooler chamber and that the warmer water in the cooling pipes is in the portion of these pipes which is inthe hotter chamber 31, so that we secure this arrangement the counterflow principle which gives a greater cooling effect.

Another important feature of my invention is the cool ngo'f the piston especially the end wall which is in contact with the gases in the combustion chamber. The gases are thoroughly cooled in the chambers 31 and 32, and as they pass through the chamber 22 in the piston and out the conductor 28 they thoroughly; cool the walls of the piston preventing carbonization of the ,oil on the.

piston mills and the format on of other carbon deposits. This insures a tight piston with no piston ring trouble and better compression. i

It is also to be noted that, unlike the usual method of cooling in which the cooling water is in direct contact with the walls of the cylinder, in my construction the cooling water is not in direct contact with the walls o1 the cylinder 10. Thus my engine will pick up much more rapidly than the ordinary tour-cycle engine with the cooling water in direct contact with the cylinder walls, that is, where the cooling water is in direct contact with the cylinder walls this;

water must be heated before the walls of the cylinder can be raised to the proper down muchlfurther, so that this engine will run without-shifting gears where the other engine would not andI'secure amuch] greater range of operation; or a greater flexi' bility. i

I secure another material advantage overthe four-cycle engine because in my engine the pressure in the-combustion chamber at the beginning of the compression stroke'is always'thesame and thus the compression secured is always the same regardless of the positionof the throttle valve, which is not true in the four-cycle engine. in idlingor travelling along a level. road the throttle or intake valve is partly closed. lhider these conditions the lour-cycle eiiginedurii'ig its suction stroke creates a partial vacuum over thepiston as usual, but the'partly closed throttle valve does not allow the cylinderto be filled with the combustible mixture and thus nocompression is secured throughout the first part of the compression stroke.

Compression is not secured until the piston approaches the upper GHClOIf its stroke. The result is that in the four-cycle engine under these conditions very little compression is" secured and the mixture will burn very slowly. In fact, it is not thoroughly burned at all and considerable power is lost by escape of unburned gases from the cylinder. Furthermore, the cylinder walls did not have a chance to heat up thoroughly during the compression stroke as littleheat was generatedpand they, therefore, absorbed considerable of the heat generated by the combustion, still further reducing the ei'ficiency; 'lhis effect is further increased by the fact that the coolingwater' is directly in contact with the cylinderwalls'. Inmy engine, however, the pressure in the combustion chamber 12 is always practically the same at thebeginning of the coinpressionstroke becauseit is determined by the pressure in the gas chai'nbers 31' and 32 which is practically constant. Therefore, the throttle valve is partly closed a portion of the burned gases will not be withdrawn from this combustion chamber and the amount of the fresh incoming chargewill be determined by the amount of the exhaust gases which have been withdrawn. I Willy therefore, always have practically the same amount of compression regardless of the po-- sition of the throttle valve so that theguses are burned under the best conditions, and}? secure a thorough and rapid combustion of thesegasesunder all conditions of operation as I secure substantially the same liighconn pression under all. conditions. The cylii'ider walls are heated practically as much by the compression when the throttle valve is parv ly open as when this valve is fully open. Thus the cylinder walls do not absorb a greater proportionof the heat under these conditions than they do when operating with the throttle valve fully open. Still further, as I have pointed, out above, in my engine the cooling water is not in direct contact with the cylinder walls so that the walls may heat up to the proper temperature, and the cooling water does not absorb such a large amount of heatduring the expansion stroke. Thus I secure practically as great eiliciency when idling or running with the throttle valve partly closed as when running with this valve fully open. It will also be apparent the engine will pick up much more rapidly and may be throttled down much further,

With my construction of engine I secure more horse power for a given weight of engine than in the four-cycleengine, as there are only two cylinders to secure the same power generated by four cylinders in the four-cycle engine. For the same reason there isonly half the piston displacement for thesame power.

In my engine while running there is always a reduced pressure or partial vacuum in the cooling or condenser chambers 31 and 32, and this vacuum sutiicient to operate vacuum brakes, vacuum gear shifts and so forth.

The power and efficiency of my engine is also increased because the back pressure on the exhaust gases as they leave the combustion chamber is greatly reduced. in fact, the back pressure is reduced below atmospheric pressure,while in the four-cycle engine it is considerably above atmospheric pressure. Another advantage of my engine is that no mufiler is required as the pressure of the gases as they are discharged into the atmosphere is only slightly above atmos pheric pressure. The pressure generated in the chamber 13 is only that required to open the exhaust valves 23.

Having thus set forth the nature of my invention, what I claim is:

1.111 an internal combustion engine, a cylinder, a piston mounted to reciprocatein saidcylinder and forming a combustion chamber at one side thereof and a pump chamber at the other side thereof, means for conducting a combustible mixture to the combustion chamber, means for conducting exhaust gases from the pump chamber; means for conducting burned gases fromthe combustion chamber to the pump chamber including a. gas chamber in the walls of the cylinder extending substantially the length of the combustion chamber and substantially surrounding itso that the cylinder walls are cooled by transfer of heat from these walls to the gases within said chamber, means forming a communication from the combustion chamber to the gas chamber, and means forming a communication from the gas chamber to the pump chamber; and means in the gas chamber for cooling the gases in said chamber.

2. In an internal combustion engine, an uprightcylinder, a piston in said cylinder forming a combustion chamber at one end of thecylinder and a pump chamber at the other end of the cylinder, an inlet to said combustion chamber at the top thereof, an outlet from the pump chamber, means for conducting gases from the combustion chamber to the pump chamber comprising a gas chamber in the cylinder walls extending substantially the length of the combustion chamber and substantially surrounding it so that the cylinder walls are cooled by transfer heat from these walls to the gases within the chamber, said gas chamber communicating with the combustion chamber at the lower end thereof, and means for cooling the gases in said gas chamber.

3. In an internal combustion engine, an upright cylinder, a piston in said cylinder forming a. crnnhustion chamber and a pump chamber, means for conducting fuel to the cmnbustion chamber at the top thereof, means for conducting exhaust gases from the pump chamber, said cylinder being prt vided with a plurality of openings communieating with the combustion chamber at; the lower part thereof: and with the pump chamber at the upper part thereof, conducting means for gases comprising a gas chamber in the walls of the cylinder extending substantially the length of the combustion chamber andsubstantially surrounding it so that the walls of said combustion chamber are cooled by transfer of heat from said walls to the gases in the gas chamber, said gas chamber extending between said openings, said piston being arranged to cover and uncover said openings to control the flow of. the gases, and cooling means for the gases in said chamber.

4. In an internal combustion engine, an upright cylinder, a piston in said cylinder forming a combustion chamber and a pump chamber respectively on opposite sides of the piston, means 1 or conducting fuel to the upper part of the combustion chamber, means for conducting exhaust gases from the pump chamber, means for conducting gases from the lower part of the combustion chamber to the pump chamber including a gas chamber inthe walls of: the cylinder extending substantially the length of the man bastion chamber and substantially surrounding it so that the walls of the combustion chamber are cooled by transfer of heat from said walls to the gases in the gas chamber, a plurality ot'pipes in said gas chamber and arranged to be surrounded by said gases, and means for causing flow of cooling fluid through said pipes.

5. In an internal combustion engine, a

lua

stroke,

cylinder, a piston in said, cylinder forming a combustion chamber and a pump chamberrespectively on opposite sides 'of'the piston, means for conducting fuel to the combustion chamber, means i for conducting exhaust gases from the. pump chamber, a gas chamber in the walls of the cylinderforming a cooling n'ieans for said walls by transfer or heat from said walls to the gases in said chamber, said cy 'nder being provided with openings leading to said gas chamber from the combustion and pump chambers, and arranged to be respectively exposed by said piston alternately at the extremes of its a partition in the gas chamber bc-- tween the openings leading from the combustion and pump chambers, conducting means communicating with the gas chamber adjacent theopposite ends thereof, and pipes for cooling fluid extending through the gas chamber. l

6,111 an internal combustion engine, a cylinder, a hollow piston in said cylinder forming a combustion chamber and a pump chamber respectively on opposite sides of the piston, means for conducting fuel to the combustion chamber, means for conducting gases from the combustion chamber to the pump chamber, means for cooling the gases in said conducting means, means for conducting the cooled gases from the pump chamber to the interior of the piston, and means for conducting said gases from the piston.

7. In an internal combustion engine, a cylinder, a hollow piston in said cylinder forming a combustion chamber and a pump chamber respectively on opposite sides of the piston, means for conducting fuel to the combustion chamber, means for conducting gases'from the combustion chamber to the pump chamber, means for cooling the gases in said conducting means, one or more ex haust valves carried by the piston and adapted to control passage of said cooled gases from the pump chamber to the interior of the piston, and means for conductingthe gases from the piston to a point of discharge. 8. In an internal combustion engine, a cylinder, a hollow piston in said cylinder forming a combustion chamber and a pump chamber respectively on opposite sides of the piston, means for conducting fuel to the combustion chamber, means for conducting gases from the combustion chamber to the pump chamber, means for cooling the gases in said conducting means, one or more valve controlled exhaust passages in the lower Wall of the piston leading from the pump chamber to the chamber within the piston, and a conductor pipe for the gases projecting through said wall and terminating adjacent the other end Wall of the piston.

9. In an internal combustion engine, a cylinder, apiston in said cylinder forming a combustion chamber and a pump chamber respectively on opposite sides of the piston, means for conducting gasesfrom the combusti on chamber tothe pump chamber including a gas chamber in the walls of the cylinderextending substantially the length of the cemlnistioncha nber and substantially surroimdii'ig it so that the walls of said comfibustion Cl1t11lll)l2ti?6 cooled by transfer of 'iluid to one of said latter chambers and from the other chamber, a valve controlled inlet leading to the combustion chamber and a valve controlled outlet leading from the pump chamber.

10/111 an. internal combustion engine, a cylinder having a gas chamber in the walls thereof surrounding the cylinder and ex tending substantially the length of said cyl inder so that the walls of the cylinder are cooled by transfer of heat from said walls to the gases in said chamber, a piston mounted to reciprocate in said cylinder, means for conducting a combustible mixture to said cylinder, connection from the cylinder to the chamber for passage of exhaust gases, a pump connected to said chamber for withdrawing the exhaust gases therefrom, means for discharging exhaust gases from the pump, and means for cooling the gases in said. chamber.

11. In an internal combustion engine, an upright cylinder, a piston mounted to reciprocate in said cylinder, means for conducting a combustible mixture to the upper part of said cylinder,an exhaust gas chamber in the walls of the cylinder and surrounding the cylinder and extending substantiallythe length of said cylinder so that the Walls of the cylinder are cooled by transfer of heat from said walls to the gases in said chamber, conducting means for exhaust gases leading from the lower part of the cylinder to said chamber, means for reducing the pressure in said chamber to withdraw the exhaust gases from the cylinder including a pump for dis charging the gases from said chamber, and means in the chamber for cooling the gases therein.

12. In an internal combustion engine, an upright cylinder, a piston in said cylinder forming a combustion chamber in the upper part thereof and a pump chamber in the lower part, means for conducting a combustible mixture to the upper part ofthe combustion chamber, a gas chamber in the walls of the cylinder and surrounding the cylinder and extending substantially the length of said cylinder so that the walls of the cylinder are cooled by transfer of heat from said Walls to the gases in said chamber, the

walls of the cylinder being provided with openings leading from the lower part of the combustion chamber to the gas chamber and from the gas chambento the upper part of the pump chamber, said openings belng arranged to be controlled by the piston, a partition in the gas chamber between the two sets of openings, gas conductors leading ALFRED O. ANDERSEN. 

